The former Alaska governor and vice presidential candidate launched a bus tour for her new book, "Going Rogue: An American Life," which is already a bestseller. The tour started Wednesday in Grand Rapids, Michigan.

Palin's last tweet occurred from an account associated with Alaska's governorship. When she resigned in late July, the @AKGovSarahPalin went dormant and Palin switched to sending out frequent Facebook messages.

This week, her old Twitter account sent a message, saying @AKGovSarahPalin would be removed and Palin would begin tweeting from a new account: @SarahPalinUSA.

Palin has more than 22,000 people following her new account. More than 153,000 people followed her original account.